1. Field of the Invention
The present invention relates to a substrate processing method and a substrate processing apparatus. Substrates subjected to processing include a semiconductor wafer, a substrate for liquid crystal display, a substrate for plasma display, a substrate for FED (Field Emission Display), an optical disk substrate, a magnetic disk substrate, a magneto-optical disk substrate, a photomask substrate, and a ceramic substrate.
2. Description of Related Art
In the production process of a semiconductor device and a liquid crystal display, processing using a processing solution is applied to a substrate, such as a semiconductor wafer and a glass substrate for liquid crystal display. To be more concrete, chemical processing is applied to the substrate by supplying a chemical to the main surface of the substrate followed by cleaning processing to cleaning away the chemical on the substrate by supplying deionized water to the main surface of the substrate to which the chemical is supplied.
The cleaning processing is followed by dry processing to dry the substrate by removing deionized water remaining on the substrate. As a method of performing the dry processing to dry the substrate, IPA (isopropyl alcohol), which is an organic solvent having higher volatility and smaller surface tension than deionized water, is applied to the main surface of the substrate after the cleaning processing for deionized water on the substrate to be substituted by IPA, after which IPA is removed from the substrate. See Japanese Unexamined Patent Publication No. 2003-92280.
However, because IPA is a water-soluble solvent, it mixes with deionized water freely, which makes the substitution of deionized water on the substrate by IPA incomplete. In other words, IPA remaining on the substrate contains a slight amount of moisture. When a solvent (IPA) having a high vapor pressure evaporates in this state, moisture having a low vapor pressure is left on the substrate. Such moisture gives rise to a pattern collapse caused by surface tension and a water mark.
Meanwhile, the same processing may be performed using a water-insoluble solvent, such as HFE (hydrofluoroether), instead of IPA. However, because it is difficult to let a water-insoluble solvent get into minute recess portions formed on the substrate. Accordingly, moisture on the substrate is not substituted by the water-insoluble solvent sufficiently, which possibly results in poor drying.